Tree Pruning and Nesting Season in CA
- Beverly Alvarez
- Apr 7
- 5 min read
Trees are essential to life, not only do they produce oxygen and store carbon dioxide, but they also provide shelter, food, and fuel. In botany, the study of plants, a tree is defined as a perennial plant that is a long term investment because it grows slowly and may not bloom or grow within the first year. It has an elongated trunk that supports branches and leaves. Many trees can grow between twelve to twenty four inches a year and can take up to 20 to 30 years to fully mature and grow. Over the lifetime of a tree, pruning is of benefit. The size of trees can range from 20 to 100 feet tall. Tree pruning is the act of tree trimming (branches, stems), not tree removal, and has been practiced for thousands of years in order to generate healthy growth and the production of abundant fruit.
Tree pruning is important because it helps maintain healthy trees by removing diseased branches. It can also protect homes or structures that are at risk of property damage from falling branches during storms (hurricanes, tornadoes, wind storms, etc). On trees that bear fruit, pruning allows the energy from the plant to focus on the healthy fruits and leaves that need to grow, instead of diverting energy to unnecessary or diseased branches. The plant will be able to develop strong limbs and absorb sunlight across evenly, yielding a higher growth.
The best time to prune is usually during late fall to early winter in order to avoid disrupting nesting birds. Even though it is easier to see through the tree structure in the winter, the California Department of Fish and Wildlife (CDFW) recommends that tree pruning should be avoided during February through August (early spring to summer) as this is nesting season for birds. If pruning is necessary during these months then it is important to look carefully for any nests or holes in trees that may be sheltering birds before beginning to prune.
The way to prune is to first identify any dead, damaged, or diseased branches. Disease can inhibit new growth and strength in a tree, therefore by removing damaged or diseased branches it will help the tree maximize delivery of water and nutrients to the healthy branches or fruit in the tree. After identification, making a proper cut is important in order to help the plant continue to grow in a way that will promote strength and health. This can happen by focusing on the branch side of the stem collar of the area that is diseased or damaged so that the tree will be able to recover and continue to grow well. Cutting mid-way through the branch is called tipping, which encourages weak branches to grow. This affects the structure of the tree and birds that depend on trees for shelter and protection may have a hard time adjusting to the altered structure.
In order to protect birds, the best option is to avoid pruning during nesting season (February through August). If trimming during this time is unavoidable, first search for any nests or holes in trees that may possibly be sheltering birds before cutting. Birds take shelter in trees in order to protect themselves from predators, harsh weather conditions like rain or snow, and to shelter their young. Many birds will shelter their chicks in trees to protect them from predators such as foxes and racoons, keeping them elevated off the ground because of how vulnerable they are. Nests in or on branch trees will allow warmth to be kept in place for the chicks to avoid cold temperatures and protect them from dying. Newly hatched chicks need to be kept at 95 degrees Fahrenheit for their first week of life, which is crucial to survival. After the first week, for the following two weeks chicks are able to survive in 80 to 90 degree Fahrenheit weather.
If a nest is spotted it is best to hold off tree trimming to allow the young birds to grow stronger until they are able to fly and relocate. If you find a nest after tree trimming it is possible, but not optimal, to relocate the nest somewhere close to the original spot of the tree—that way the mother bird is able to come back and view her nest. Tree trimming in the presence of a bird nest puts the young birds in danger of abandonment from their caregiver due to loud noises or fear. If a nest is beyond repair it is encouraged to call a local wildlife center for advice or help.
For many birds, nesting season is between the months of February to August, but there are exceptions and birds that do not use typical nests. The California Spotted Owl, also known as Strix occidentalis, is a native bird that will nest during the winter in mature trees. The Nutall’s Woodpecker, also known as Dryobates nuttallii, will create holes in trees for nesting. Anna’s hummingbird, scientifically known as Calypte anna, will also nest near the middle end of branches that lie 10 to 15 feet off of the ground. Migratory hummingbirds’ breeding season will start in December and extend through May or June, meanwhile non-migratory hummingbirds in Southern California nest from late October to early June.
Considering nesting season when tree pruning is essential so that any native or endangered bird species in California can be kept safe not only by wildlife services, but also by the community! A reason to avoid pruning during nesting season is that nesting birds are sensitive to human disturbances such as loud noises which can lead them to abandon their eggs and nests. Pruning branches can also crush bird eggs or cause the nesting bird to leave.
There are a few ways to be involved and active in protecting nesting birds in SoCal. One is to consult a professional arborist to prune trees, since they are aware of regulations and nesting habits and can practice it while being bird friendly by avoiding any unnecessary cutting. Another is to consider delaying any pruning if a nest is found to ensure the eggs or young birds can grow strong and healthy until they are able to leave the nest. Bird feeders can also encourage birds to nest in nearby trees.
For any further regulations, the California Fish and Game Code (FGC) contains several sections to help protect birds, their eggs, and nests. Taking these steps and simply being informed is a big step to protect wildlife!
Works Cited:
Neolithic Age Technology | Overview & Importance - Lesson | Study.com.
- Growth & Development | California State Parks
Age of the Giant Sequoias | National Park Service
How Long Does It Take for a Tree To Grow? 45 Trees Ranked by How Fast | 8 Billion Trees
Native Plants for birds | Theodore Payne Foundation
Hummingbirds and what you need to know about them in your yard and garden | The Orange County Register
California Outdoors Q&A - nesting birds | California Department of Fish and Wildlife
Feeding Wild Birds Can Carry Risks: Here’s How to Minimize Unintended Harms | Blog | Nature on PBS
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